Synthesis of several cytokinin glycosides will be accomplished. The agents will be examined for their ability to support or block tissue growth in plant cells in culture. The materials will also be submitted to evaluation in tests of their ability to suppress tumor growth in mammalian systems. Additionally several Thiazolo(5,4-d)pyrimidine cytokinin analogs will be prepared and their biological properties evaluated. It is expected that these materials will give information about the necessity for glycoside formation for biological activity.